The city known for detonating its past to make way for gleaming new development on the Las Vegas Strip is preparing to push out its Sept. 11 memorial.

The shrine on the Las Vegas Strip sprung up spontaneously under the ersatz skyline of the New York-New York casino in the days after the terrorist attacks. For more than a decade, a rotating collection of first responder T-shirts from across the country, many bearing handwritten notes, has decorated a wrought-iron fence near the faux fireboat below the casinos' 47-story replica of the Empire State Building.

Now, MGM Resorts International is starting a $100 million renovation of the promenade in front of 16 year-old Manhattan-themed casino and the adjoining Monte Carlo. The memorial will have to go.

MGM says it will relocate the shrine, which has remained a heartfelt marker amid the plastic artifice of the desert playland.

"We are working with representatives of the First Responder community in Las Vegas to identify and determine an appropriate and permanent placement of the memorial to the victims of September 11th," MGM spokesman Clark Dumont said in a statement Friday.

On Friday morning, several quiet bulldozers and a pile of rubble sat around what remained of the display.

In 2003, the University of Nevada, Las Vegas began collecting the T-shirts, hats and handwritten notes left at the memorial. It now stores nearly 6,000 of the artifacts in plain office boxes at the university library. Curators rotate the memorabilia through a permanent display case that MGM opened in 2003 at the foot of the resort's 150-foot model Statue of Liberty.

Gambling professor David Schwartz, who oversees the university's involvement with the memorial, said he hopes MGM will relocate the display somewhere equally visible.

"It would be nice to have the public be able to view the shirts still. It's something unique to Vegas, though of course the tragedy affected everybody," he said. "When we first got the shirts and we were going through them, just seeing the messages people who had lost someone had written kind of drove the horror of the whole thing home."

MGM is in the process of transforming the congested sidewalks in front of its New York City and European-themed casinos into an outdoor plaza featuring trees, benches, food trucks and shops. The new promenade is intended to recall Madison Square Park.